When an high powered explosive (simply put ..a bomb) detonates on earth (God forbid!), high intensity shock waves in the range of about 5000 lb/sq.inch are created in the surrounding air. A massive pressure wave is created followed by an equally destructive suction wave. A very loud bang is heard followed by heavy destruction!

But the high intensity pressure waves exist due to the presence of air in our atmosphere. If the same bomb goes off in vacuum (say in space), there is no air and shock waves would be absent (I guess).

So, what will be the nature or behavior of the explosion if the bomb detonates in an atmosphere free of gases or air (ideally vacuum)? Will one hear a loud bang . or no sound would be heard since there is no air to create the massive mechanical forces of pressure and suction? If mechanical forces are present, what kind of energies will they emit?Valuable comments/inputs will be appreciated.

There was the experimental nuclear detonation out of atmosphere over hawaii. No Bang, but most to the power grid went down.

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But will there be emission of heat or flames? What about mechanical forces like shockwaves........ if glass breaks due to explosion in vacuum, then there has to be mechanical forces involved! But how can pressure or suction waves be present in the absence of air?

Well, I would say that the molecules of the explosive materials would undergo their reaction, generating heat just as on Earth. The heat would gassify all the molecular products of the reaction, which would then expand outwards because of the imbalance of pressure on the molecules. There'd be an initial pulse of electromagnetic radiation that would expand in an ever-enlarging sphere. Behind that, the heated molecules would also expand in a sphere of ever-increasing size.

I imagine that if you were in a spacesuit nearby, then you'd feel the impact of the expanding gas. If you were close enough, you probably would hear it as a sound, since your spacesuit could be slapped with a powerful force.

Without atmosphere to slow the molecules, they would continue to travel at a initially high velocity, slowing only by the gravitational attraction between the particles, but as they expand in the 3-dimensional volume of space, the pressure per area would decrease with distance from the explosion, so if far enough away, the overall force of the particles striking you would decrease to the point that at a great enough distance, nothing would be heard or felt.

But will there be emission of heat or flames? What about mechanical forces like shockwaves........ if glass breaks due to explosion in vacuum, then there has to be mechanical forces involved! But how can pressure or suction waves be present in the absence of air?

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Sure there was a shock that broke the glass, even though it was initially under vacuum. The reaction was between sodium/potassium amalgam, which renders those alkali metals liquid at room temperature, a chlorinated hydrocarbon, and some other hydrocarbons. The resulting free-radical reaction caused plenty of gas to be released quickly.

But back to your question, shock waves are pressure waves, which cannot travel through a true vacuum. However, shock waves are evident in stellar nebulae, so it doesn't take much pressure to allow propagation.

Just for context, I remember being impressed with how many molecules were still present in the highest vacuum we could easily achieve in the 1960's (about 10^-7 mm Hg). Look up "Mean Free Path" in Wikipedia for a good table.

In brief, an ultra-high vacuum of about 10^-7 mm Hg still has about 10^9 particles per cm^3.